Feature Request: Support DATE_PART syntax as an alias for EXTRACT

[murphyatwork]

Description
StarRocks currently supports the EXTRACT(field FROM source) function to obtain specific parts of a date or timestamp. However, many users coming from PostgreSQL or Snowflake are more familiar with the DATE_PART(field, source) syntax.

To improve compatibility and ease migration, StarRocks should support DATE_PART as a syntax sugar (alias) for EXTRACT.

Proposal

• Add support for DATE_PART('field', datetime_expr)
• Semantics should be identical to EXTRACT(field FROM datetime_expr)
• Supported fields: year, month, day, hour, minute, second, dow, doy, etc.

Examples

SELECT DATE_PART('year', TIMESTAMP '2025-09-02 13:45:00');
-- Expected: 2025

SELECT DATE_PART('dow', TIMESTAMP '2025-09-02 13:45:00');
-- Expected: 2

Use Cases

• Simplifies migration from PostgreSQL/Snowflake.
• Improves developer experience by allowing familiar syntax.

[sfwang218]

@murphyatwork Hi, could you please assign this issue to me? I would like to give it a try.